How do I dismantle a rear brake caliper?

[Maz]

The rear brake caliper on my Allez keeps the brake blocks pressed against the rim when the brake is released.

I think I need to give it a good clean out and re-grease (the return spring looks a bit rusty and gritted up too) -too much crud build-up with no mudguards on, probably.

How do I take off the caliper to clean it? The whole unit is bolted to the frame with what looks like a hex-bolt, and there's another hex-bolt on one side of the caliper itself.

Anyway, does anyone know how to take the caliper off? Is this an easy job?

Thanks

 

[PatrickPending]

The rear brake caliper on my Allez keeps the brake blocks pressed against the rim when the brake is released.

I think I need to give it a good clean out and re-grease (the return spring looks a bit rusty and gritted up too) -too much crud build-up with no mudguards on, probably.

How do I take off the caliper to clean it? The whole unit is bolted to the frame with what looks like a hex-bolt, and there's another hex-bolt on one side of the caliper itself.

Anyway, does anyone know how to take the caliper off? Is this an easy job?

Thanks

it is a kind of hex bolt that fits through the back. easy to remove

theres one here

http://www.madison.co.uk/products.a...onents+&+Hardware&tier2=Nuts,+Bolts+&+Washers

theyre rescessed bolts - cant remember the size, good luck!

 

[Maz]

it is a kind of hex bolt that fits through the back. easy to remove

Thanks - I tried to get a good look at it (wheel is in the way) and seems like a sort of hex/star-shaped bolt.
I'd need to take the rear wheel off to gain access to it, clearly.
Many thanks.

 

[Maz]

it is a kind of hex bolt that fits through the back. easy to remove

theres one here

http://www.madison.c...lts+%26+Washers

theyre rescessed bolts - cant remember the size, good luck!

Yes, that looks like it (top left). Will have to have a close-up look later. Thanks.

 

[2Loose]

Yes, that looks like it (top left). Will have to have a close-up look later. Thanks.

You should be able to see a bit easier on the front caliper - behind the fork crown.
Undo it all the way and then pull the caliper away from the rear stays. Depending on brake cable tension this may be a bit stiff.

When putting it back on, clamp the brake while tightening to keep them centred.

 

[ASC1951]

How do I take off the caliper to clean it?

You may not need to. You can do almost as thorough a job with a good squirt of WD40 followed by lots of fiddly flossing with a couple of baby wipes. With a bit of practice you can clean every part of the assembly except the inside of the spindle hole and behind the return spring.

I only remove and strip down the calipers every couple of years, if that.

 

[swee'pea99]

Dare I ask whether you've checked the cable? When my brakes get sticky like that, it's generally a sign that the cable needs oiling - down the housing, and especially where it goes round the BB. I'm not saying this is the problem or will fix it, but that's where I'd start.

 

[Maz]

Good question. No, I haven't checked the cables (I've never ever checked the cables before!).
What sort of oil should I use for this?

 

[Amanda P]

Swee'pea has a good point.

Consider lubricating or replacing the cable first. That could well solve the problem.

Sometimes, as the brake blocks wear, they develop a little step which hooks on the edge of the rim and stops the brake disengaging when you let go of the lever. If this is what's happening, replace the blocks, or, if you're sure there's lots more wear in them, remove them file the faces flat, and re-fit.

If none of these things helps, then, yes, a strip and clean might be in order. Do this carefully because there are dozens of thin washers which all need to go back in the right places if it's to work well. Lay them out on a clean sheet of paper in order, and don't drop any!

 

[Maz]

Swee'pea has a good point.

Consider lubricating or replacing the cable first. That could well solve the problem.

Sometimes, as the brake blocks wear, they develop a little step which hooks on the edge of the rim and stops the brake disengaging when you let go of the lever. If this is what's happening, replace the blocks, or, if you're sure there's lots more wear in them, remove them file the faces flat, and re-fit.

If none of these things helps, then, yes, a strip and clean might be in order. Do this carefully because there are dozens of thin washers which all need to go back in the right places if it's to work well. Lay them out on a clean sheet of paper in order, and don't drop any!

Thanks. When I first noticed the problem, I looked down at the brakes, which were already very worn, so I put new ones on straight away. Still got the sticky caliper problem, though, of course.

Hopefully a good oiling will sort it...I'm now put off from dismantling the caliper!

What sort of oil, please?

 

[ChrisKH]

Also check the wheel is true. I messed about with Junior KH's brakes, eventually replaced them then realised the wheel was out of true and not put back on correctly..............

 

[swee'pea99]

As to what sort of oil, any light oil really. 3-in-1 is fine, or anything similar. Try to support your bike somehow so gravity helps run the oil down the cable housing (the tube it runs through) - I hang it off 'er indores's hanging flower basket bracket - then try to run oil down the cable, drip by drip, giving it time to go into the tube. Working the brakes at the same time can help it penetrate. Anything that gets the cable moving. 

 

[PpPete]

By the way - check for any fraying / loose strands of cable too. Replace the inner if so.

Was working on a bike the other day ... Brakes were fine, but I was changing a 27" wheel for a 700C so had to move the pads in the calipers, by the time I'd fiddled with it, spring wasnt returning calipers to open position. Oil didn't help - but when I pulled the inner cable out there one loose strand that had come 'unravelled' and was creating a huge amount of friction in the outer.

 

[John Ponting]

A short video is worth many many words http://bicycletutor.com/

 

[Maz]

Problem sorted...oiled the brake cable/housing and the brakes are working fine now.
Calipers opening/closing OK now.
Thanks for all your help.